Diet and Weight-Loss Lore, Myths, and Controversies

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Chapter 9
Diet and Weight-Loss Lore, Myths, and Controversies

Some people manage to modify their weight through effective lifestyle change, but many turn repeatedly to drastic, short-term, and ultimately ineffectual weight loss methods or to self-inflicted serious semi-starvation with its attendant negative physical and psychological consequences.

—Joel Yaeger, M.D., Department of Psychiatry, University of New Mexico School of Medicine, in "Weighty Perspectives: Contemporary Challenges in Obesity and Eating Disorders," American Journal of Psychiatry, vol. 157, no. 6, June 2000

One of the challenges facing public-health professionals as they seek to combat obesity among Americans is helping consumers to distinguish myths, lore, legends, and outright fraud from accurate, usable information about nutrition, diet, exercise, and weight loss. Some of these inaccuracies are so longstanding and deeply rooted in American culture that even the most educated consumers unquestioningly accept them as facts. Others began with a kernel of truth but have been so wildly distorted or misinterpreted that they are confusing, misleading, or entirely erroneous. The rapid influx and dissemination of information about the origins of overweight and obesity and conflicting accounts of how best to treat these problems compound the challenge. With media reports and advertisements trumpeting different diets nearly every week, it is no wonder that Americans are confused about diet and weight loss.

The fiction that people who are overweight or obese are lazy and weak-willed is among the most harmful myths because it serves to promote stigma, bias, and discrimination. Another common misconception is that it is equally easy or difficult for all people to lose weight. There are biological and behavioral factors that affect an individual's body weight, and people vary in terms of genetic propensity to become overweight, basal metabolic rate (BMR), and number of fat cells. BMR, often referred to simply as "metabolic rate," is the number of calories an individual expends at rest to maintain normal body functions. BMR changes with age, weight, height, gender, diet, and exercise habits and has been found to vary by as much as 1,000 calories a day. Differences in metabolic rate explain, in part, why not all people who adhere to the same diet achieve the same results in terms of pounds lost or rate of weight loss. Another factor that produces variation in weight loss is the number of fat cells in the dieter's body. Although fat cells do not determine body weight, they are affected by weight gain and act to limit weight loss since their number cannot be decreased. For example, a normal-weight person has about forty billion fat cells while an individual who weighs 250 pounds with a body mass index (BMI) of 40 may have as many as 100 billion fat cells. Weight loss causes fat cells to shrink in size but does not decrease their number. As a result, individuals with twice as many fat cells as normal-weight people may be able to shrink their fat cells to a normal size but even when they have attained a healthy weight will still have twice as many fat cells.


It is impossible to recount all of the fantastic and improbable claims that have been made in recent years. This section considers some of the most persistent myths about diet, exercise, and weight loss.

Low-Carb Diets


A low-carbohydrate diet is the fastest, healthiest, best way to lose weight.


Low-carbohydrate diets initially may produce more rapid weight loss than other diets; however, most of the loss is water weight rather than fat. The water loss occurs as the kidneys flush out the excess waste products resulting from digestion of protein and fat. Many low-carbohydrate diets encourage consumption of high-fat foods, such as butter, heavy cream, bacon, and cheese. Long-term, high-fat diets may raise blood cholesterol levels, and low-carbohydrate, high-protein diets produce a state of "ketosis" (the accumulation of ketones from partly digested fats as a result of inadequate carbohydrate intake), which may increase the risk of gout (a severe arthritis attack that occurs in one joint—typically the big toe, ankle, or knee—caused by defects in uric acid metabolism) and kidney stones. Further, most nutritionists and researchers concur that while some weight-loss diets are nutritionally inadequate and others are even dangerously insufficient, nearly all diets can affect weight loss, and currently, no compelling evidence exists to proclaim one diet vastly superior to another. A key factor in the success of any weight-loss diet is adherence—whether dieters can remain faithful to the regimen they have chosen, and to date, low-carbohydrate diets have not demonstrated superiority in terms of adherence. Boredom and frustration with a low-carbohydrate regimen may occur when dieters crave the carbohydrates that they are forbidden or can eat only in very small amounts. In a first-person account of low-carbohydrate dieting, "Low-Carb Fast-Food Dinner Leads to Bun Envy" (Sacramento Bee, February 1, 2004), journalist Anita Creamer lamented that "Lettuce is not a bun. And low carb, the diet craze du jour, is not a lifestyle to be embraced by the faint of heart, or by the hungry." She also posited that carbohydrate deprivation may lead to crankiness or moodiness, observing that "low carb partly accounts for the gnawing, low-level unhappiness of women in the 1950s and 1960s. Baby boomers' mothers were always on diets, trying to fit into slender pedal pushers and dresses with nipped waistlines. For weeks on end, they starved themselves on hamburger patties, boiled eggs and iceberg lettuce, and for exercise, they flew into ketonic rages." Creamer's account confirms what nutritionists and obesity researchers have long known—that diets will not work unless people stick to them.

In 2004 researchers at Tufts-New England Medical Center compared two calorie-restricted diets—a high glycemic index (GI)/high-carbohydrate diet with a low-GI/low-carbohydrate diet and found that the diets performed equally well in terms of weight loss and increase in insulin sensitivity. The investigators monitored insulin sensitivity because of concern that a carbohydrate-heavy diet with a high glycemic load could contribute to diabetes and insulin resistance. About three-quarters of the subjects in both groups were women with an average age in the mid-thirties and an average BMI of 27.6 kg/m2 at the beginning of the study. After six months, an analysis of the subjects revealed that subjects using either diet had a 10% reduction in BMI and a more than 20% increase in insulin sensitivity (Anastassios G. Pittas, NAASO 2004 Annual Scientific Meeting: Abstract 40-OR. November 16, 2004).

Calorie Reduction


You need to cut calories drastically to lose weight.


Weight loss may be accomplished with modest reductions in calorie consumption. Low-calorie diets often result in metabolic adaptations, such as a significant reduction in resting metabolic rate, which may produce weight maintenance or even weight gain rather than the desired weight loss. Many nutritionists and diet plans advise simultaneously reducing total caloric-intake and modifying the balance of macronutrients (nutrients that the body uses in relatively large amounts—proteins, carbohydrates, and fats)—some weight-loss diets reduce fat intake, others reduce carbohydrates.

Negative-Calorie Foods


It takes more calories to eat and digest some foods such as celery or cabbage than these foods contain and as a result, eating them causes or speeds weight loss.


There are no foods that when eaten cause weight loss. Foods containing caffeine may temporarily boost metabolism but they do not cause weight loss. However, some recent evidence suggests that eating grapefruit or drinking grapefruit juice may help people who are obese to lose weight. Ken Fujioka and his colleagues at the Scripps Clinic in San Diego, California, compared weight loss over a twelve-week period among 100 obese individuals. One-third of the subjects ate half a grapefruit before each meal three times a day, while another drank a glass of grapefruit juice before every meal. The third group did not include grapefruit in their meals. In "Grapefruit Diet Works and May Prevent Diabetes" (Chemistry & Industry, No. 3, February 2004), the researchers reported that after twelve weeks, subjects who ate grapefruit lost an average of 3.6 pounds, and those who drank grapefruit juice lost an average of 3.3 pounds while those in the control group who consumed no grapefruit lost an average of 0.5 pounds. The researchers attributed the weight loss to lowered levels of insulin, which were confirmed by measurements of blood glucose and insulin levels. They posited that the more efficiently sugar is metabolized, the less likely it is to be stored as fat. Further, lowering insulin levels reduces feelings of hunger—elevated insulin levels stimulate the brain's hypothalamus, producing feelings of hunger.

Eating at Night


Eating after 8:00 pm causes weight gain.


Weight gain or loss does not depend on the time of day food is consumed—excess calories will be stored as fat whether they are consumed mid-morning or just before bedtime. In general, weight is governed by the amount of food consumed measured in total calorie count, and the amount of physical activity expended during the day.

Natural Weight-Loss Products


Organic, natural, or herbal weight-loss products are safer than synthetic (produced in the laboratory) over-the-counter or prescription drugs.


Simply because products are organic or naturally occurring does not necessarily mean that they are risk-free or safe. For example, in July 2003 the Federal Trade Commission (FTC) took action against marketers of weight-loss products containing ephedra, which is derived from a leafless desert shrub, and hydroxycitric acid, which is an extract from brindall berries. The actions targeted deceptive effectiveness, safety, and side-effect claims for weight-loss supplements containing these dietary supplements. The FTC challenged advertising claims that ephedra and other natural supplements caused rapid, substantial, and permanent weight loss without diet or exercise, as well as the claims that these weight-loss products are "100% safe," "perfectly safe," or have "no side effects."

Low-Fat and Low-Carb Foods


"Low fat" or "no fat" means few or no calories.


A low-fat or nonfat food is usually lower in calories than the same size—as measured by weight—portion of the full-fat food; however, a food product can contain 0 grams of fat and still have a high calorie content. Many fat-free foods replace the fat with sugar and contain just as many or more calories as full-fat versions. While most fruits and vegetables are naturally low in fat and calories, processed low-fat or nonfat foods may be high in calories because extra sugar, flour, or starch thickeners have been added to enhance the low-fat foods' taste or texture.

Similarly, low-carb foods are often higher in calories than their "regular" counterparts because their fat content is higher. Many foods that are naturally low in carbohydrates such as meat, butter, and cheese are also calorie-dense. Many nutritionists suggest limiting consumption of low-carb versions of foods, such as low-carb frozen desserts because they not only contain as many or more calories per serving than ice cream but also are often sweetened with non-nutritive artificial sweeteners.

Eliminating Starchy Foods


Pasta, potatoes, and bread are fattening foods and should be eliminated or sharply limited when trying to lose weight.


Potatoes, rice, pasta, bread, beans, and some starchy vegetables such as squash, yams, sweet potatoes, turnips, beets, and carrots are not innately fattening. They are rich in complex carbohydrates, which are important sources of energy. Further, foods that are high in complex carbohydrates are often low in fat and calories since carbohydrates contain only four calories per gram compared to the nine calories per gram contained by fats. In "Effects of an Ad Libitum Low-Fat, High-Carbohydrate Diet on Body Weight, Body Composition, and Fat Distribution in Older Men and Women: A Randomized Controlled Trial" (Archives of Internal Medicine, vol. 164, no. 2, January 26, 2004), Nicholas Hays and his colleagues reported the results of a small study that found that dieters lost substantial amounts of weight on a high-carbohydrate, low-fat regimen. Meals were prepared for the subjects, who were told to eat as much as they wanted and to return any uneaten food, which enabled the researchers to calculate the subjects' calorie intake. Surprisingly, subjects who consumed a high-carbohydrate, low-fat diet with no quantity or caloric restrictions lost significant amounts of weight. The researchers speculated that low-fat, high-carbohydrate diets may reduce body weight via reduced food intake, since complex carbohydrate-rich foods are more satiating and less energy-dense than higher-fat foods and concluded that their "data support the alteration of dietary macronutrient composition without emphasis on caloric restriction as an effective means of promoting weight loss."

Genetic Destiny


People from families where many members are overweight or obese are destined to become overweight.


It is true that studies of families have found similarities in body weight and that immediate relatives of obese people are at increased risk for overweight and obesity compared to people with normal-weight family members. Although it is generally accepted that genetic susceptibility or predisposition to overweight or obesity is a factor, researchers believe that environmental and behavioral factors make equally strong, if not stronger, contributions to the development of obesity. As a result, people from overweight or obese families may have to make concerted efforts to maintain healthy body weights and prevent weight gain, but they are not destined to become obese simply by virtue of the genes they inherited.

Exercise Alone


Exercise is a better way to lose weight than dieting.


While there are numerous health benefits from exercise, weight loss is not generally considered a direct benefit. Research has consistently demonstrated that for weight loss, diet trumps exercise because it is simpler to reduce caloric intake significantly through diet than to increase caloric expenditure significantly through exercise. For example, if a 155—pound person wished to reduce his or her consumption by 400 calories per day, it might be achieved by simply eliminating dessert and reducing portion sizes. In contrast, expending 400 calories requires considerable effort. To burn 400 calories, a 155—pound person would have to spend about an hour bicycling at about ten miles an hour; playing basketball, hiking cross country, mowing the lawn, or ice skating at nine miles per hour; or water skiing or walking uphill at about 3.5 miles per hour. However, many studies have demonstrated that exercise is an important way to prevent overweight and maintain weight loss.

Cris Slentz and his colleagues at Duke University Medical Center found that as little as thirty minutes of walking daily is enough exercise to prevent weight gain for most sedentary people, and exertion above that may even cause weight and fat loss. In "Effects of the Amount of Exercise on Body Weight, Body Composition, and Measures of Central Obesity: STRRIDE—A Randomized Controlled Study" (Archives of Internal Medicine, vol. 164, no. 1, January 12, 2004), the investigators reported the results of their study in which 182 overweight, inactive adults aged forty to sixty-five were randomly assigned to one of three programs of escalating exercise or to a control group that did not exercise for eight months. One group did the equivalent of twelve miles of walking per week, another completed the equivalent of twelve miles of jogging per week, and the most intense exercise group performed exercise comparable to jogging twenty miles per week. All of the exercise was performed on treadmills, elliptical trainers, or stationary bicycles in supervised settings. The subjects were encouraged not to change their diets during the study.

Subjects in the two low-level exercise groups lost weight and fat, and those in the most intense exercise program lost more weight and fat than the others. The vigorous exercise group had a 3.5% weight loss, the two low-dose groups had slightly more than a 1% weight loss, while the control group had a 1.1% weight gain. Exercise dose and intensity also determined changes in waist circumference—subjects who did not exercise had a 0.8% increase in waist circumference. The two groups doing the lower amounts of exercise had decreases of about 1.5%, and the most intensely exercising group reported a waist decline of 3.4%. The investigators determined that a modest amount of exercise—thirty minutes a day—can prevent weight gain without changes in diet.

Exercisers' Diets


People who exercise have healthier diets than those who don't work out.


It is a common misconception that by simply embarking on an exercise program people spontaneously improve their diets and make healthier food choices. Although starting to exercise regularly represents a commitment to improved health and wellness, and diet and exercise resolutions are often made together, a recent study revealed that exercisers do not necessarily "eat better." In "Effects of Sixteen Months of Verified, Supervised Aerobic Exercise on Macronutrient Intake in Overweight Men and Women: The Midwest Exercise Trial" (American Journal of Clinical Nutrition, vol. 78, no. 5, November 2003), Joseph Donnelly and his colleagues from the Center for Physical Activity and Weight Management, Energy Balance Laboratory, and the Department of Dietetics and Nutrition of the University of Kansas, and the Department of Pediatrics at the University of Colorado Health Sciences Center, questioned whether moderate aerobic exercise led to changes in diet, specifically, an increased carbohydrate intake and decreased fat consumption. The investigators assigned seventy-four sedentary, overweight to moderately obese people aged seventeen to thirty-five to one of two groups. The first group engaged in supervised moderate-intensity exercise for forty-five minutes per day, five days a week, and was advised to maintain their usual caloric intake. The other group was told simply to maintain their usual level of physical activity and caloric intake. After sixteen months the investigators found no significant differences between the groups in terms of fat, carbohydrate, or protein intake. The investigators also reported that the exercisers mistakenly believed that "they could eat what they wanted as long as they were exercising."

Eating Disorders


Eating disorders occur exclusively among middle- and upper-class white females.


Like many myths about diet, weight, and nutrition, this one is based on fact—an estimated 90% of people with anorexia nervosa or bulimia nervosa are female; however, according to Susan Yanovski, "Eating Disorders, Race, and Mythology" (Archives of Family Medicine, vol. 9, no. 1, January 2000), binge-eating disorder occurs in both genders and across socioeconomic classes. Yanovski attributes the myth that eating disorders are limited to middle- and upper-class white women to the fact that many studies were conducted on college campuses where few minority students were enrolled, and other research looked at people seeking treatment, often at referral centers. Yanovski observed that "studies done on such populations, which may be more likely to be white and of higher socioeconomic status, have limited generalizability." She also cited research that found that minorities are substantially affected by eating disorders—one study found that African-American women were as likely as white women to report binge eating. Another revealed that the prevalence of binge eating was comparable among Hispanic, non-Hispanic white, and African-American women, but that binge-eating symptoms were more severe among the Hispanic group. Yanovski concluded that "Recognition that eating disorders are color-blind can ensure that appropriate recognition and treatment are available to all patients at risk."


Most diets do not fail—they work to produce weight loss. Historically diets have been considered to have "failed" when lost weight is regained. Many nutritionists and obesity researchers believe that diets fail because most are not sustainable. The more restrictive the diet, the less likely an individual will be to remain faithful to it because in general, people cannot endure extended periods of hunger and deprivation. Another reason diets may fail is that they neglect to teach dieters new eating habits to assist them to maintain their weight loss. Most overweight people gained their excess weight by consuming more calories per day than they needed. Dieting creates a temporary deficit of calories or specific macronutrients such as carbohydrates or fat. Since the weight-loss diet is viewed as a temporary measure with a beginning and an end, at its conclusion, most dieters return to their previous eating habits and often regain the lost weight or even more weight. Many nutritionists and dieticians who work with people who are overweight or obese assert that diets do not fail, instead dieters fail to learn how to eat properly to prevent weight regain.

Consumers are not the only ones who believe diets are doomed to failure; many health professionals and researchers cite the statistic that 95% of diets fail. The American Obesity Association (AOA) attributes this oft-cited statistic to Albert Stunkard of the University of Pennsylvania and a director emeritus of the AOA. Stun-kard put forth the 95% failure rate in an account of research he performed in 1959, which involved advising 100 overweight patients to diet, with no follow-up or support to increase their adherence to the diet. In an editorial published on the AOA Web site, "Why Don't They Get It?" (, March 1, 2002), Morgan Downey, AOA executive director, observed that this statistic has been applied to every existing weight-loss program from surgery and antiobesity drugs to group support and behavior-modification programs. Downey wondered why such an old statistic, derived from such a small sample of subjects who had been offered nearly no counseling other than a printed diet, would still be cited almost a half century after its publication. He speculated that "It may be that it actually reflects people's own experience. Or it may be used to discourage vigorous weight loss efforts. Maybe some of us with obesity find it helpful to have company in our own weight loss failures."

Improving Long-Term Weight Loss

More recent research has demonstrated that dieters find it challenging to maintain weight loss; however, it has refuted the 95% failure rate. In "Successful Weight Loss Maintenance" (Annual Review of Nutrition, vol. 21, no. 1, July 2001), Rena Wing and James Hill proposed defining "successful long-term weight loss maintenance as intentionally losing at least 10% of initial body weight and keeping it off for at least one year." Using this definition the investigators offered more favorable outcomes of weight-loss efforts. Wing and Hill reported that more than 20% of overweight or obese people can and do lose 10% or more of body weight and maintain the weight loss for more than a year. Analyzing data from the National Weight Control Registry, they also found that people who successfully maintained long-term weight loss—an average weight loss of 30 kg (66.14 lbs) for an average of 5.5 years—shared common behaviors that promoted weight loss and weight maintenance. These behavioral strategies included eating a diet low in fat, frequent self-monitoring of body weight and food intake, and high levels of regular physical activity. The investigators also posited that weight-loss maintenance may become easier over time because they observed that once weight loss had been maintained for two to five years, the chances of longer-term success were greatly increased.

Although Wing and Hill offered more optimistic estimates of successful weight loss and weight maintenance than Stunkard had reported, there is obviously considerable room for improvement. Research supported by the National Institute of Diabetes and Digestive and Kidney Diseases and National Heart, Lung, and Blood Institute and led by Robert Jeffery, Division of Epidemiology, School of Public Health, University of Minnesota, attempted to identify areas of investigation that might produce strategies to assist more people to control their weight effectively ("Long-Term Maintenance of Weight Loss: Current Status," Health Psychology, vol. 19, no. 1, supplement, January 2000). Jeffery and his colleagues asserted that despite high rates of dieting and the possibility of long-term success in voluntary weight loss overall, successful weight losses are being offset by failures. The investigators speculated that the reason for this overall lack of success is that improvements in long-term weight loss have thus far lagged behind improvements in short-term weight loss.

Jeffery and his colleagues, one of whom was Albert Stunkard, described the typical course of weight loss and regain among people participating in behavioral treatment for obesity as rapid initial weight loss that slows, with maximum weight loss achieved approximately six months after treatment began. Thereafter weight regain begins and continues until weight stabilizes at, or slightly below the starting weight. The investigators speculated that the behavior changes prescribed are sufficient for weight loss, and failure to maintain behavior changes may be due to loss of knowledge and skills, loss of motivation, or unpleasant side effects of behavior change such as hunger, psychological stress, or social pressure. Historically, researchers favored either a biological interpretation of the challenge of weight maintenance—the importance of biological determinants of body weight—or a behavioral explanation. Behavioral scientists interpreted the weight loss—weight regain pattern as evidence of how difficult it is to achieve lasting change in environmental factors that influence behaviors.

The investigators classified efforts to improve long-term maintenance of weight loss as attempts to increase the intensity of initial treatment, extend the length of treatment, alter dietary and exercise prescriptions, enhance motivation, and teach maintenance-specific behavioral skills. An example of high-intensity obesity treatment is use of very-low-calorie diets (VLCDs). VLCDs restrict food intake for periods of two to three months to 600-800 calories per day, substantially lower than conventional low-calorie diets, which range from 1,000-1,200 calories per day. VLCDs consistently produce larger initial weight losses than conventional low-calorie diets. However, they have not proven successful in improving long-term weight loss. The larger, rapid weight losses generated by severe calorie restriction are followed by larger and more rapid regains, which offset the initial losses. Two or more years after treatment, people who were placed on VLCDs fared no better than those who lost weight using less intense regimens.

Treating obesity like such chronic diseases as diabetes and high blood pressure that require ongoing management appears to be helpful; however, attendance at treatment sessions declines over time and is associated with weight regain. Efforts to modify dietary and exercise prescriptions have focused on emphasizing exercise instead of focusing solely on dietary changes. Although some studies showed that the addition of exercise improved short-term weight loss and weight loss at eighteen-month follow-up visits, exercise was found to slow but not prevent weight regain.

Approaches to enhance motivation have focused on two areas—tangible financial incentives and improved social supports. Several studies found that modest payment as a reward for weight loss did not enhance initial weight loss nor did it slow the rate of regain after initial weight loss. Strategies to improve social supports have emphasized including spouses or significant others in the weight-loss process to teach them to provide social support for their partners' weight-loss efforts. Such strategies have demonstrated modest success as have contracts in which groups agreed to aim for individual or group weight-losses.

Teaching patients skills that are useful for weight maintenance as opposed to weight loss emphasizes that there are two distinctly different sets of strategies—one set focuses on weight loss and the other on maintaining a stable energy balance around a lower weight. The most commonly used model for teaching maintenance-specific skills is relapse prevention, which involves teaching people to identify situations in which lapses in behavioral adherence are likely to occur, to plan strategies in advance to prevent lapses, and to get back on track should they occur. Relapse prevention is based on the idea that breaking the "rules" in terms of remaining faithful to diet and exercise programs may often lead to negative psychological reactions that in turn prompt reversion to pre-weight-loss behaviors. To date, only one study has examined the effectiveness of this approach. Researchers hypothesized that learning and practicing a well-defined, positive response to relapses might help people sustain weight losses. However, their findings did not support this hypothesis.

Jeffery and his colleagues acknowledged that weight management is a continuing source of fascination and frustration for researchers as well as dieters. They recommended that research consider additional areas including:

  • Considering obesity as a chronic disorder requiring continuous care, with the aim of developing cost-effective methods for delivering care indefinitely
  • Examining psychological, behavioral, biological, and environmental factors that relate to weight loss, maintenance of weight loss, and weight regain in order to identify the key factors associated with successful long-term weight loss
  • Improving the assessment of energy intake and expenditure and of behavior patterns associated with change in energy intake and expenditure
  • Examining the role of such behavioral preferences as inclination for energy-dense foods and physical activities in obesity and its treatment in an effort to answer such questions as "Can behavioral preferences or reinforcement values be changed in ways that would facilitate long-term weight loss? Do they change spontaneously after behavior changes?"
  • Researching why long-term outcomes of behavior treatment for obesity in children and adolescents have been more successful than treatment for obesity in adults
  • Learning more about the role of physical activity and social support in relationship to long-term weight loss
  • Discovering safer and more effective medications to treat obesity and developing new ways to integrate medications into effective programs of weight control


There is a long history of marketing "miraculous," fat-burning pills, potions, and products to Americans seeking effortless weight loss. In Fat History: Bodies and Beauty in the Modern West (New York: New York University Press, 2002) and Losing It: False Hopes and Fat Profits in the Diet Industry (New York: Penguin USA, 1998), authors Peter Stearns and Laura Fraser offered detailed histories of magical cures and weight-loss fads. At the turn of the twentieth century such products as obesity belts and chairs that delivered electrical stimulation, as well as corsets, tonics, and mineral waters, claimed to cause weight loss.

Diet pills arrived on the scene in 1910 with the introduction of weight-loss tablets that contained arsenic (a poisonous metallic element), strychnine (a plant toxin formerly used as a stimulant), caffeine, and pokeberries (formerly used as a laxative). In the 1920s cigarette makers promoted their products as diet aids, urging Americans to smoke rather than eat. During the 1930s diet pills containing dinitrophenol, a chemical used to manufacture explosives, dyes, and insecticides, enjoyed brief popularity after it was observed that factory workers making munitions lost weight. Their popularity was short-lived, as cases of temporary blindness and death were attributed to their use.

The second half of the twentieth century saw the proliferation of questionable, and often entirely worthless, weight-loss devices and gimmicks, including inflatable suits to "sweat off pounds," diet drinks and cookies, and slimming creams, patches, shoe inserts, and wraps to reduce fat thighs and abdomens. Although the claims made for many of these products sounded too good to be true, unsuspecting Americans spent billions of dollars in the hope of achieving quick, easy, and permanent weight loss.

Weighing the Claims

In May 2000 the Partnership for Healthy Weight Management, a coalition of scientific, academic, health care, government, commercial, and public interest representatives, initiated consumer and media education programs that not only aimed to increase public awareness of the obesity epidemic in the United States but also to promote responsible marketing of weight-loss products and programs. The Partnership published a consumer guide, Finding a Weight Loss Plan That Works for You, designed to help overweight or obese consumers find weight-loss solutions to meet their needs. The guide contained a checklist to enable consumers to compare weight-loss plans based on a variety of criteria. (See Table 9.1.) It also advised consumers about how to select weight-loss programs and services based on specific information from potential providers. The costs of producing the new consumer guide were shared by several of the more than fifty partner organizations, including the International Food and Information Council, the Centers for Disease Control and Prevention, the National Institute of Diabetes and Digestive and Kidney Diseases, and Novartis Nutrition Corporation.

The coalition partners also launched the "Ad Nauseam" campaign to encourage the media to demand proof before accepting advertising copy that contained unbelievable, dubious, or extravagant promises of weight-loss success. The campaign pledged to:

  • Publish an annual list of claims made in ads during the previous year for products or services that promise results so extravagant that any responsible media outlet should have demanded proof before accepting them for publication
  • Identify the media outlets that published or broadcast the questionable ads
  • Identify media indicating they have adopted strategies to screen out dubious advertising claims for weight-loss products

Table 9.2 lists some of the dubious claims the Partnership uncovered during 1999 and 2000. The Partnership also invited the public to participate in identifying questionable weight-loss advertisements and asked consumers to send such ads and the publications they appeared in to the Federal Trade Commission (FTC).

In 2002 the FTC reported that as much as 55% of advertising for weight-loss products and services contained false or unsupported effectiveness claims (Weight Loss Advertising: An Analysis of Current Trends [Washington, DC: Federal Trade Commission, 2002]). Nearly 40% of the 300 advertisements reviewed by FTC staff made at least one assertion that was most likely false and an additional 15% made at least one representation that was very likely false, or in the best cases, lacked adequate substantiation. The report also observed that despite an unprecedented law enforcement effort in the decade preceding the FTC study, the incidence of false and deceptive weight-loss advertising claims appeared to have increased.

On November 19, 2002, the FTC convened a workshop attended by researchers, scholars, media experts, and medical professionals from the government, academia, and private industry that aimed to evaluate claims and develop new and more effective ways to combat false and deceitful weight-loss advertising claims. The FTC summarized the workshop proceedings, including attendees" assessments of eight broad categories of advertising claims, in Deception in Weight-Loss Advertising Workshop: Seizing Opportunities and Building Partnerships to Stop Weight-Loss Fraud (Washington, DC: Federal Trade Commission, 2003). The following section considers the advertising claims and summarizes the attendees" assessments of these claims presented in the December 2003 FTC report. It also draws on an analysis of the FTC report by Stephen Barrett in "Impossible Weight-Loss Claims: Summary of an FTC Report" (, December 16, 2003).


Dubious weight loss claims

  • "'I LOST 93 POUNDS!… QUICKLY, EASILY & NO DIETING." New. Now Available Without A Prescription…. People have reported losing the first 10 pounds within a few days and up to 50 pounds the first month. Even if you want to lose 100 or more pounds [product name] can be your answer."
    'I Lost 44 POUNDS in 30 DAYS'
    NEVER be fat again with the [product name]
    … The [product name] eliminates fat for effortless weight loss. Same results as: Jogging 10 miles per week. An hour of aerobics per day. 15 hours of swimming or cycling per week."
  • "The Miracle of Body Fat Reduction. Where do you want to lose weight? It's the same for everyone. Body fat always gravitates to the stomach, the buttocks, the hips and legs [Product name] will help to rapidly reduce the fat in all these areas. It does this by redirecting these problem fat cells to the muscles of the body where it can be burned off more easily. By taking just one tablet before every meal, the weight gaining process can be averted by simply maintaining the same plan."
    • NO EFFORT REQUIRED: eat every thing you normally eat
    • NO RISK TO YOUR HEALTH: no fatigue, no side effects, no mood changes. A 100% natural method to lose weight
    • NO DIETING EVER: no food restrictions, or exercise programs
    • NO CONSTRAINTS OF ANY KIND: your day to day activities do not change. The only change is how much better you will look."
  • Imagine Losing As Much as 50% Of All Excess Fat In Just 14 Days! NOT EVEN TOTAL STARVATION CAN SLIM YOU DOWN AND FIRM YOU UP THIS FAST-THIS SAFELY!… LOSE UP TO 1 FULL POUND EVERY 8 HOURS. LOSE UP TO 2 1/2 TO 3 FULL POUNDS EACH DAY and you do it without counting calories."
  • "Amazing Fat Fighting Pill Ends Hunger—Guarantees Super Fast Weight Loss! U.S. Patent reveals weight loss of as much as 28 lbs. in 4 weeks and 48 lbs. in 8 weeks … There now exists an all natural, bio-active weight loss compound so powerful, so effective, so relentless in its awesome attack on bulging fatty deposits that it has virtually eliminated the need to diet … Eat all your favorite foods and still lose weight (pill does all the work)."
  • "This extraction of sweet acids contained in tropical fruits will allow anyone, including those who have never succeeded in losing weight, to activate their metabolism and lose up to 14 pounds per week."
  • "New Medical Breakthrough! 'Lose A Pound A Day Without Changing What You Eat' … You will get a risk free opportunity to get the trim, sexy body you've always dreamed of in days or weeks, instead of months or years, without going through painful excerise and unbearable diets."
  • "WATCH FAT MELT AWAY WITH [product name]. No impossible excerise! No missed meals! No dangerous pills. No boring foods or small portions! Just fast and easy, effective weight loss! [Product name] is the easiest way to successfully lose weight you'll ever try. It doesn't require gruelling excerise. There are no dangerous pills or tablets to take. Best of all, you continue to eat your favorite foods!"
  • "The new fat-fighter. Slimming capsules that soak up fat!… This brand new Swiss formulated high power diet-pill has been created and discovered by Dr. ______ M.D., for men and women to lose weight and bind fat from foods you have eaten. The idea is as brilliant as it is simple. Have you ever seen an overweight fish? Or an oyster with a few pounds too many? Everyone knows that sea animals never get fat. That's because their bodies contain [product name] which is now available as a diet pill for everybody who wants to lose unwanted fat. [Product name] reduces body fat deposits in the belly, thighs, and butt. It also makes sure that the fat from your last meal leaves your body before being digested."
  • "NOW EVERYONE CAN EASILY BURN OFF EXCESS WEIGHT WITHOUT CHANGING DIET OR TAKING EXCERISE!… You do not have to change the food you eat. This is not a starvation diet—and you do not have to take gruelling pointless excerise. [Product name] starts incinerating your fat and slimming your figure from day one. It is 100% natural so it is totally safe. We guarantee that you'll lose between 2 and 8 pounds a week until you reach your target weight and sexy figure—and you won't put the fat back on!"
  • "You lose with weight even if you eat too much. These active pineapple [product name] tablets that you can now receive on a free trial basis force your body to dissolve all its excess fat. You should know that 8 tablets contain the weight loss power of 16 whole pineapples. Consequently, even if you continue to eat normally, even if you eat too much, you are literally forced to lose your excess pounds. You will lose at least 16 pounds in the first two weeks. And at least six pounds every week thereafter."

source: "Ad Nauseam: The Year 2000 Ads Nauseam Include the Following Dubious Claims," in Ad Nauseam, The Partnership for Healthy Weight Management, Federal Trade Commission, Bureau of Consumer Protection, 2000, (accessed January 13, 2006)

No Diet or Exercise Required


The advertised product causes substantial weight loss without exercise or diet.


"U.S. patent reveals weight loss as much as twenty-eight pounds in four weeks … The pill does all the work, and Lose up to two pounds daily without diet or exercise."


The consensus was that products purporting to cause weight loss without diet or exercise would either need to cause malabsorption of calories or to increase metabolism. Since the number of calories that can be malabsorbed is limited to 1,200 to 1,300 calories per week, or about one-third of a pound per week, malabsorption alone is unlikely to lead to substantial weight loss. Similarly, there is no thermogenic (heat producing) agent, such as ephedrine combined with caffeine, able to boost metabolism enough to produce weight loss without diet or exercise. In fact, the mechanism by which ephedrine products appear to assist weight loss is by suppressing appetite rather than speeding metabolism. Further, though green tea extract was found to increase metabolism, it was by a scant 4%.

No Restrictions on Eating


Users can lose weight while still enjoying unlimited amounts of high calorie foods.


"Eat All the Foods You Love and Still Lose Weight (Pill Does All the Work)"


This claim was viewed as a variation of the assertion that dieters can lose weight without reducing caloric intake or increasing exercise, since this claim states that users not only can lose weight without reducing caloric intake but also may increase caloric intake and still lose weight. The assembled experts concurred that if this claim was true, it would defy the laws of physics.

Permanent Weight Loss


The advertised product causes permanent weight loss.


"Take it off and keep it off; You won't gain the weight back afterwards because your weight will have reached an equilibrium; People who use this product say that even when they stop using the product, their weight does not jump up again."


Even if a product caused weight loss through a reduction of calories, appetite suppression, or malabsorption, weight would be regained once use of the product stopped and calorie consumption returned to previous levels. Researchers and health professionals have repeatedly observed that dieters tend to regain weight lost over time once the diet, intervention, or other treatment ends. According to the National Academy of Science, Food and Nutrition Board, "Many programs and services exist to help individuals achieve weight control. But the limited studies paint a grim picture: those who complete weight-loss programs lose approximately 10% of their body weight only to regain two-thirds of it back within one year and almost all of it back within five years." Further, there are no published scientific studies supporting the claim that a nonprescription drug, dietary supplement, cream, wrap, device, or patch can cause permanent weight loss.

Fat Blockers


The advertised product causes substantial weight loss through the blockage or absorption of fat or calories.


"The [named ingredient or product] can ingest up to 900 times its own weight in fat, that's why it's a fantastic fat blocker. The Super Fat Fighting Formula inhibits fats, sugars and starches from being absorbed in the intestines and turning into excess weight, so you can lose pounds and inches easily."


Science does not support the possibility that sufficient malabsorption of fat or calories can occur to cause substantial weight loss. To lose even one pound per week requires malabsorption of about 500 calories a day or about 55 grams of fat. To lose two pounds per day, as promised in some advertisements, would require the malabsorption of 7,000 calories per day, which is impossible given that it is several times the total calories that most people consume on a daily basis, let alone the number of calories consumed from fat. The FTC has challenged deceptive fat-blocker claims for some of the most popular diet products on the market. The evidence supports the position that consumers cannot lose substantial weight through the blockage of the absorption of fat. It is not scientifically feasible for a nonprescription drug, dietary supplement, cream, wrap, device, or patch to cause substantial weight loss through the blockage of absorption of fat or calories.

Quick Weight Loss


The user of the advertised product can safely lose more than three pounds a week for time periods exceeding four weeks.


"Lose three pounds per week, naturally and without side effects."


Significant health risks are associated with medically unsupervised, rapid weight loss over extended periods of time. In general, "the more restrictive the diet, the greater are the risks of adverse effects associated with weight loss." One of the best-documented risks is the increased incidence of gallstones. The claim that consumers using products such as these without medical supervision can safely lose more than three pounds per week for a period of more than four weeks is not scientifically feasible.

Weight-Loss Creams and Patches


The advertised product that is worn on the body or rubbed into the skin causes substantial weight loss.


"Lose two to four pounds daily with the Diet Patch; Thigh Cream drops pounds and inches from your thighs."


Diet patches and creams that are worn or applied to the skin have not been proven to be safe or effective. Further their alleged mechanisms of action are not scientifically credible.

Guaranteed Success


The advertised product causes substantial weight loss for all users.


"Lose excess body fat. No willpower required. Works for everyone no matter how many times you've tried and failed before."


This claim assumes that overweight and obesity arise from a single cause or are amenable to a single solution. Since the causes of overweight and obesity are thought to be genetic factors and environmental conditions, and such contributing factors as diet, metabolic rate, level of physical activity, and adherence to weight-loss treatment vary, it is highly unlikely that one product would be effective for all users. Even FDA-approved, prescription drugs for weight loss have a high level of nonresponders, and gastric bypass surgery for obesity is not successful 100% of the time. The claim that a nonprescription drug, dietary supplement, cream, wrap, device, or patch will cause substantial weight loss for all users is not scientifically feasible.

Targeted Weight-Loss Products


Users of the advertised product can lose weight from only those parts of the body where they wish to lose weight.


Testimonial advertising has included such claims as "And it has taken off quite some inches from my butt (5 inches) and thighs (4 inches), my hips now measure 35 inches. I still wear the same bra size though. The fat has disappeared from exactly the right places."


Small published studies of aminophylline cream indicate that its use may cause the redistribution of fat from the thighs to other fat stores; however, it has not been shown to cause fat loss. Even if some products were determined able to cause more weight loss from certain areas of the body, no parts would be spared completely—fat is lost from all fat stores throughout the body.

Red Flag Campaign and "Big Fat Lie" Initiative Target Phony Weight-loss Claims

Another outcome of the November 2002 workshop was the design of another education initiative to assist the media to voluntarily screen weight-loss product ads containing claims that are "too good to be true." The media were targeted for intensive education not only because broad-based public education had proven largely inadequate to protect consumers from persuasive messages trumpeting easy weight loss, but also to acknowledge the media's powerful ability to reduce weight-loss fraud by sharply reducing the dissemination of obviously false weight-loss advertising. On December 9, 2003, the FTC launched its "Red Flag" campaign to more effectively assist the media to reduce deceptive weight-loss advertising and promote positive, reliable advertising messages about weight loss.

In April 2004 the FTC filed claims against seven companies for making false weight-loss claims, and in November 2004 the FTC announced six new cases against advertisers using bogus weight loss claims. In each of these cases, the Commission sought to stop the bogus ads and to secure reparation for consumers. The same month, the FTC launched "Operation Big Fat Lie," a nation-wide law enforcement action against the six companies making false weight-loss claims in national advertisements. Operation Big Fat Lie is the latest program in the Commission's effort to stop deceptive advertising and provide refunds to consumers harmed by unscrupulous weight-loss advertisers; encourage the media not to carry advertisements containing bogus weight-loss claims; and educate consumers to be wary of companies promising miraculous weight loss without diet or exercise.


While the majority of Americans are overweight, a small number of people are experimenting with extremely low-calorie diets in the hope that by remaining extremely thin they will stave off disease and live longer. Advocates of extreme caloric restriction (CR) contend that sharply reducing caloric intake creates biochemical changes that slow the aging process, which theoretically should increase life expectancy.

Although most people would find it impossible to adhere to semi-starvation diets, there is sound scientific evidence that subsistence diets increase the life spans of fruit flies, worms, spiders, guppies, mice, and hamsters by between 10% and 40%. In theory, semi-starvation prolongs life by reducing metabolism—how quickly glucose is used for energy—in an evolutionary adaptation to conserve calories during periods of famine. Dieters are familiar with this process—they know from experience that as they eat less, their metabolic rates drop, and it becomes increasingly more difficult to lose weight. CR adherents experience comparable drops in metabolic rate—one study found that their body temperature dropped by a full degree. Proponents of CR assert that while metabolism is vital for life it also is destructive, producing unstable molecules known as "free radicals" that can damage cells through a process called oxidation.

Animal studies have found that CR inhibits the growth of cancerous tumors, possibly because at lower body temperatures the body may be better able to repair damaged DNA. (Deoxyribonucleic acid molecules carry the genetic information necessary for the organization and functioning of most living cells and control inheritance of traits and characteristics.) Animals on calorie-restricted diets have reduced levels of blood sugar and insulin and greater insulin sensitivity, which reduce their risk for diabetes and cardiovascular disease. There is even evidence that CR boosts brain function. Mice with the tendency to develop such neurological conditions as Alzheimer's or Parkinson's diseases developed these conditions later and more slowly when they were placed on CR diets, and rodents on CR diets displayed better memory and learning than those on normal diets. There is also evidence that CR influences patterns of gene expression. As animals age, certain genes tend to "turn-off" and become inactive while others are activated. CR has been found to prevent 70% of change in gene expression in mice.

During 2004 the National Institutes of Health began a seven-year study to explore the effect of CR on human metabolism. The study is exploring the benefits and risks associated with CR. CR adherents report immediate health benefits including increased mental acuity, reduced need for sleep, sharply reduced cholesterol and fasting blood sugar levels, weight loss, and reduced blood pressure. The regimen is clearly not easy, and even its staunchest advocates, and members of the Caloric Restriction Society, concede that many people who practice CR experience constant hunger, obsessions with food, mood disorders such as irritability and depression, and lowered libido. CR can also cause people to feel cold, and even with adequate vitamin and mineral supplementation, can cause some people to suffer from osteoporosis (decreased bone mass) and hair loss.

In 2005 evolutionary biologists John Phelan of the University of California, Los Angeles, and Michael Rose of the University of California, Irvine, challenged the notion that caloric restriction would increase longevity. The scientists concluded that severely restricting calories over decades may add a few years to a human life span, but will not enable humans to live to 125 years or older. The investigators developed a mathematical model based on the known effects of calorie intake and life span that showed that people who consume the most calories have a shorter life span, and that if people severely restrict their calories over their lifetimes, their life span increases by between 3% and 7%—far less than the twenty-plus years some hoped could be achieved by drastic caloric restriction. The investigators opined that "Longevity is not a trait that exists in isolation; it evolves as part of a complex life history, with a wide range of underpinning physiological mechanisms involving, among other things, chronic disease processes." They advise Americans to "Try to maintain a healthy body weight, but don't deprive yourself of all pleasure. Moderation appears to be a more sensible solution" ("Why Dietary Restriction Substantially Increases Longevity in Animal Models but Won't in Humans." Ageing Research Reviews, vol. 4, no. 3, August 2005).

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Diet and Weight-Loss Lore, Myths, and Controversies

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